File won't save in CS5 but does in CC need to make it back compatible

Question

This is my script, it runs fine in Photoshop CC but not on CS5.1 It does most of the script but will not save it comes up with the error
  save current document in file "Images3:2013-2014:WK99:Top:Top_WK99_PSD:TM15WA00124SV1RH.png" of current document as PNG with options {class:PNG save options, compression:1, interlaced:false} without copying
  --> error number -1728
Result:
error "Adobe Photoshop CS5.1 got an error: Can’t get current document." number -1728 from current document
set theFolder to POSIX path of (choose folder with prompt "Select Folder")
set theFolder2 to text 1 thru -2 of theFolder
log theFolder2
set dtF to paragraphs of (do shell script "find  " & quoted form of theFolder2 & " -iname \"*.PSD\"")
set tc to (count dtF)
repeat with i from 1 to tc
          set thefile to item i of dtF
          tell application id "com.adobe.Photoshop"
  activate
  open (alias thefile) showing dialogs never
                    set display dialogs to never
                    set thePath to do shell script "dirname " & quoted form of thefile
                    set SaveLocation to (POSIX file thePath) as string
                    set origName to name of current document
                    set myPNGOptions to {class:PNG save options, compression:1, interlaced:false}
                    tell current document
  --If the quick mask mode has been left on then delete the channel Quick Mask
                              try
  --for CS5
                                        if (quick mask mode) then delete channel ¬
                                                  "Quick Mask"
                              on error
  --for CS6 and up
                                        if (quick mask mode) then delete channel ¬
                                                  "Alpha"
                              end try
  --If the Layer is incorrectly labeled with Original Layer it needs renaming to original Image
                              if (exists layer "Original Layer") then ¬
                                        tell layer "Original Layer" to set name to "Original Image"
                              (delete layer "Original Image")
  --set hS to current history state
                              delete layer "BACKGROUND" of layer set "Dodge and Burn"
                              move layer "Main Image" of layer set "Dodge and Burn" to after layer set "Dodge and Burn"
                              delete layer set "Dodge and Burn"
  delete layer set "Retouch"
  trim basing trim on transparent pixels
  save in (SaveLocation & origName) as PNG with options myPNGOptions without copying
                              close without saving
                    end tell
          end tell
          set FileLocation to (POSIX file thefile) as string
          tell application "Finder" to delete FileLocation
end repeat

Answer 1

Older versions of Photoshop do not support png with compression.